It is known that carbon microspheres having a particle diameter smaller than 1 .mu. can be produced by techniques utilized for the production of carbon black such as furnace black or channel black. It is, however, extremely difficult to obtain carbon microspheres having a particle diameter in the range of from 1 to 20 .mu.. Even if carbon microspheres of such a small size are obtained, they generally tend to exhibit a phenomenon wherein several adjacent carbon microspheres adhere to form a fused cluster. Therefore, it is not easy to obtain, with high selectivity, discrete carbon microspheres having a particle diameter of 1-20 .mu.. Methods for the production of carbon microspheres or hollow carbon microspheres resistant to mutual cohesion have been disclosed in the specification of U.S. Pat. No. 3,786,134, U.S. Ser. No. 215,416, filed Jan. 4, 1972 and U.S. Ser. No. 401,160, filed Sept. 27, 1975 and owned by the same assignee as that of the present invention. These methods all relate to the manufacture of carbon microspheres having particle diameters not smaller than 30 .mu.. Thus, these methods cannot be directly applied to the production of carbon microspheres having a particle diameter of the order of 1-20 .mu..